LED lights of blue light can damage the eye?

LED lamp is after the incandescent lamp, fluorescent lamp and energy-saving lamp of a new type of light source, high luminous efficiency, but lots of people with its luminous principle and spectral characteristics do not understand, hard to avoid can worry about it will light damage to the eyes.

Three colors of leds

From the spectrum, with leds light with the traditional incandescent lamp and fluorescent lamp light is very different, the so-called "spectrum" is refers to the objects of light due to a "rainbow".

The traditional incandescent lamp, fluorescent lamp light, like the sun, has a "red, orange, yellow, green, blue, violet" these 7 kinds of color.

However, generally only the LED light of the "RGB" this 3 kinds of color, which R is red, red light; G the green, it is green; And B said blue, is blue light.

These 3 kinds of color LED to 400 nm to 500 nm of "blue LED" is the most important, is also the most basic.

Where is the blue?

Look at the this "rainbow" picture. From left to right, followed by uv, visible and infrared light. In which the wavelength of visible light range is from 400 nm to 700 nm, and from 400 nm to 500 nm wavelength range is blue, so the band is called blue light.

The basic unit of light called photons, the wavelength of the photon is inversely proportional to the frequency and the wavelength of the blue light is short, so high frequency. According to Albert Einstein and Max Planck's formula of photon energy, we can know the photon energy is equal to the product of the Planck constant and the frequency of the photon, so blue photon energy is better than red light and green light, which we can use blue to "stimulate" out of the other colors of light, such as the yellow light can be blue "shock".

Blue LED technology has won the Nobel Prize for physics

Blue LED technology in 1998 was developed, the technology also won the 2014 Nobel Prize for physics. The blue LED is on this looks tall GaN chip and yttrium aluminum garnet (YAG) wrapped together. GaN chip blu-ray, lambda equals 465 nm wavelength, wavelength bandwidth is about 30 nm.

White LED is how a white light?

So, what is how to produce the kind of white LED home of white light? In this paper, we have already said, on the blue light photon energy is high, so use it can stimulate fluorescence. General with a blue LED the blu-ray on yellow light produces in the fluorescent powder (similar to the principle of fluorescent lamp, fluorescent lamp light is ultraviolet light in fluorescent lamp tube wall from phosphor powder on). Yellow light is blue light stimulated, together they shot out from the inside of the LED, I will feel as if to see the white light, actually this is just a blue and yellow colors mixed together compound light.

We make a example, blue is "mother", and the yellow light is "son", they are both groups constitute the "white" the single parent families.

Because of this principle, so a lot of manufacturers in order to improve the brightness of white LED, directly increase the intensity of the blue light, yellow light, that may increase, and finally form the brightness of the white light is increased, but this will cause we will be in this paper to explain the "excessive" blu-ray.

The actual measure LED light spectrum

Below are different types of white LED the spectrum of the measured curve, we can see between 400 nm to 400 nm, "blue" is a very strong peak.

Life LED blue light of excessive testing standards

Generally speaking, the normal manufacturer marketed products through national quality inspection, not blu-ray excessive risks. But there are some LED lights manufacturer does not pay attention to control the intensity of the blue, blue in their production of LED lamps and lanterns is "excessive", there are blue light radiation damage to the eyes.

Life, there are many can emit blue light source -- bath bully, flat-panel displays, LED neon, fluorescent, LCD monitor, tablet, phone, etc are background light source, they contain short wave blue light. If the blue is "excessive", will affect the retina, so should avoid using eyes light source, and pay attention to the use of time, eye closure every 20 to 30 minutes to rest for a while.

If you're worried about buying LED lights or other electric equipment has the problem of "excessive" blu-ray, can according to the law of the People's Republic of China national standard GB/T 20145-2006 / CIE S/E: 20145, 2002 (the lamp and the light of the lamp system, security), to determine the blue leds is excessive, the standard blu-ray are given in the specific space Angle of upper limit of the luminous flux. (the content of the specific standards for the tadpoles king will no longer be detailed here, interested readers can refer to.)

For sale on the market of LED lights, however, how to determine the LED blue light overload is a complicated problem. Below this kind of LED lights, for example, the voltage and frequency is released from its unable to calculate whether blu-ray quantity, because the voltage and frequency is electrical indicator, and blue light is a kind of optical indicator. And its claim to "flux" is an optical indicator, but it is only the total flux of white light instead of blue light flux, so the average consumer is hard to figure out whether this light blue too much.